To open a long path or go that path which contains the spaces follow this rule:
cd "the path of the directory"
or if you want to open in GUI way i,e in any file manager.
nautilus "the path of the directory"
i,e start the path with a double quote (") and keep pressing the Tab key. Pressing the tab key will automatically show the directory you want to open.
for example, to open your path in file manager or in terminal it self:
nautilus "/media/rajan/EXTRA/BACKUP/EXTRA/OS AND TOOLS/"
or
nautilus /media/rajan/EXTRA/BACKUP/EXTRA/"OS AND TOOLS"/
or if you want to just go to the path then this command:
cd /media/rajan/EXTRA/BACKUP/EXTRA/"OS AND TOOLS"/
Reply if still you are not clear.